24 MORPHOLOGY AND EVOLUTION
and in the cerebral arteries of the Caraivora. No *aphenous artery is present- as in the Anthropoid Apes.
The blood does not give positive precipitin reactions with thut of the higher Primates.
The Organs of Respiration and Voice.—The epiglottis projects up into the naso-pharynx, the so-called intranarial position. The ventricles of the larynx do not become prolonged into air sacs. In Indris, which is distinguished by its loud voice, and in Lemur varius, a laryngeal sac communicates with the larynx through an opening close to the cricoid cartilage (Milne Edwards and Otto). Muscular fibres form isolated bundles close to the thyro-arytenoid muscle (Duckworth), The trachea! cartilages are complete in many species, and in this respect the Lemurs differ from the higher Primates. The left lung has three lobes and the right one has four, of which one is termed the azygos lobe or lobus irnpar. Its relation to the heart has already been described.
Urogenital Organs.—The left kidney is lower than the right one, the reverse of the condition present in the higher Primates; and one papilla only is present. The testes descend into a scrotum and there is a cremaster muscle derived from the transversalis abdominis or internal oblique muscle. The vesiculae seminales are absent in Chiromys; in other forms they open on the verumontanum (Weber). The penis has no corpus spongiosum in Nycticebits. But an os penis is present in all species; its extremity is bifid or spinulose.
The uterus is bicornuate, and the urethra traverses the clitoris for a variable distance.
The Brain (fig. 12):—Professor Elliot Smith (148) has pointed out that the brain in Chiromys is inter-